Technical Field
Embodiments described herein are related to the field of integrated circuits, and more particularly to power management of an integrated circuit.
Description of the Related Art
Some integrated circuits (ICs), including some systems-on-a-chip (SoCs) may include various functional circuits with different power supply voltage levels. A power supply rail may be utilized to provide power with a particular voltage level to functional circuits using the particular voltage level. Some functional circuits may receive power from multiple power rails, as different portions of a given functional circuit may use different voltage levels. For example, to conserve power, a first portion of a circuit may utilize a low voltage level when it is operating in a reduced power mode and a higher voltage level when fully operational. A second portion of the circuit may utilize a third voltage level, higher than the low voltage level of the first portion of the circuit, in the reduced power mode and the higher voltage level when fully operational.
In some cases, the first portion of the circuit may be coupled to a first power supply signal that is adjustable between the low voltage level and the higher voltage level, while the second portion of the circuit is coupled to a second power supply signal that is adjustable between the third voltage level and the higher voltage level. In the reduced power mode, the first and second power signals may be set to the low voltage level and the third voltage level, respectively. When the circuit is to be fully operational, both the first and second power supply signals may be set to the higher voltage level. If an SoC includes several circuits that utilize multiple power signals, then a power supply for the SoC may generate many different power supply signals to allow each circuit to utilize suitable voltage levels.